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Power Problem?

10-10-2006, 08:04 AM

To start, I will say our house is about 50 years old with 100amp service. About 1200 square feet. The breakers & box are only a couple years old (I replaced them with the help of friend as the OLD breakers were failing and no longer made). The problem is this, my wife tells me that every time I fire up a power tool the whole house dims. I have noticed this my self on occasion when just the well pump comes on. What do you think the cause and fix would be? I seem to recall this was happening BEFORE installing the new breaker box as well as after.

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I recently purchased a new home this summer. It currently has a 100-amp service; the home was built in the mid 60’s, when the refrigerator turns on the lights dip in the house. When the central air kicks on you know it, the lights all dim and if the microwave is running when the air kicks on the food takes longer to cook. All of our appliances are Gas however the panel is full and there seems to be no reason for the way it was wired. My garage (lights and outlets), outside lights and living room outlets are on the same circuit. The kitchen outlets, washer, drier and one bedroom are on a circuit, and many other circuits are similarly set up. I have gotten 2 quotes so far for upgrading to 200-amp service. My two quotes are $1,700, and $2,100 I am actually leaning toward the lower priced on as this electrician will bring a generator and power my refrigerators while he does the work. My local PoCo has said that the will come out after the job is done to see if the transformer needs to be upgraded and if the wires to the house need to be upgraded, these 2 upgrades are at no cost to me. once I get this upgrade done I plan on breaking up some of the circuits so that the load is more orderly distributed and shutting off or tripping the breaker for the garage won’t cause the TV in the living room to go off.

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Ump...I had the same types of problems when I purchased a home built in 1922 in 2000. The house had been upgraded somewhere in the 60s or 70s to 100amp service but only 9 circuits in the house and nothing to the detached garage. Cooking, heating, clothes drying and hot water are gas. However, hair dryers and window a/c would get breakers tripping. We still have the same 100amp service, but the house now has 19 single pole breakers and two double pole breakers feeding a 30amp subpanel in the detached garage and a 60amp subpanel for central a/c. The garage has a full complement of stationary power tools (TS, RAS, MITER SAW, JOINTER, etc.). At no time do lights dim when power tools or the central a/c activate. Proper power distribution is as important, maybe more important, than the amount of service, within reason. The major electric consumers for me are the fridge and central a/c. I'd check distribution first before spending any money upgrading service. Spend two hours mapping what outlets and lights are on what breakers. You'll probably find out that a few home runs, probably to the kitchen and any bathrooms, will alleviate many problems.

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Voltage drop is normally just too much current in too small (or long) a wire. As stated earlier you will have to carefully check your voltage at a few points (incoming service, load breaker, first recepticle, final recepticle) without the load and then again as you turn the load on. The in-rush current for a transformer and/or motor will draw much more current for a short period of time than the normal operating current, hence the momentary dimming of the lights. This can get worse if the motor is started under load (pump or compressor).

Unfortunately this could be an undersized (or too long) wire in a couple of different places; from your utility connection to the house panel (if the service is less than 100 amp), from the panel to the first load, and down the line. Careful measurements should tell you what point (node) is dropping the most and that will lead you to the wire with the maximum line losses (voltage drop).

The simplest may be to run a dedicated wire to your load, I tend to go one size larger (down one gauge) than code for my tool recepticles. Unfortunately the solution may be a electrical service upgrade (and service connection wire size increase) which could be expensive (depending if it is an overhead or underground service). There may be line devices available for sudden in-rush current (capacitors or soft starter) but these are probably not practical for home service.

Last point, may electronic devices have an auto-transformer to handle varying line voltages, however, extended severe voltage drop could cause damage to some devices

JC

JC

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Well, I just had the power company out to check the line from the pole. Was informed that while is was OK, my incoming service is only 60 amp. Also the at the connection from the house in should be replaced.

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FINER9998
I have started mapping out my existing breaker panel and have found that I could safely redistribute the load on the breakers in the existing 100-amp box however we have planes of refinishing the basement rooms and adding several new lighting fixtures, outlet and a second oven for the house. This second oven will go into the bar area and will be electric. We do a lot of baking and entertaining and a second oven will make that easier, in addition we are going to be remodeling the kitchen, removing the separate wall oven and cook top and installing a combination gas range with an microwave/hood. I am also going to install a new exhaust fan in the kitchen to replace the inoperable one that is there. Being that I will be adding to the total load of the house going to 200-amp seem to be the logical thing to do. That in addition if I choose to add a hot tub or another electrical appliance in the future I will have the power already there. I feel that the price for the installation will only go up in the future and if I can afford to upgrade now I should.

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I have never had an issue with 100A service but also run gas stove, water heater, dryer and furnace. That said I put in 200A service when I built my current house so I can run power to my out building from the house and the 200A panel is way larger so I will have lots of slots to wire the basement and 100A (takes 8 slots) breaker for the shop. The price difference was only $500 from the builder. How much do they want for the 100A service?

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Pretty much everything but the hot water & heat are electric. Those being gas. Well pump, washer, dryer, stove, dishwasher, fridg. Out in the shop .....TS,dc,mts,jointer. Two other notes, someone suggested that 200amp service would cost more to have (monthly service). And also that the lights dimming would not be corrected by simply upping the amps. but that changing the original line between the meter and the breaker panel could! So I'm still not sure what to make of it all?

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Based on your load list, and the fact that you have electric heat and live in Michigan, you may want to consider the 200amp. Also this will give you some spare capacity incase you decide to add anything else.